Radial engine



Nov. 18, 1952 G. D. ANGLE 2,618,253

RADIAL ENGINE Filed June 15, 1947 2 sHEETs sHEET 1 0 INVENTOR Glenn .3.44229459 M ATTORNEYS Nov. 18, 1952 G, D, A LE I 2,618,253

RADIAL ENGINE Filed June 15, 1947 2 SHEETS-SHEET 2 INVENTORGZezznflAzyZ'e ATTORNEYS Patented Nov. 18, 1952 UNITED STATES PATENTOFFICE 2,618,253 RADIAL ENGINE Glenn Angle, Thomaston, ConnaassjignortoiThe; N Br a ne o p n w Britain, Conn, a corporation of ConnecticutApplication-June 13, 1947, Serial No. 754,556

scams. (o1. fee-19s) My invention relates to reciprocating engines, andin particular to radial internal-combustion engines as employed inaircraft.

A primary object of theinvention' is to provide a. simple radial-engineconstruction that will permit improved methods of assembly.

Another object is to provide an'improved engine construction that 'ma'ybe fabricated at a reduced cost and that will be inexpensive tomaintain.

A further object is to provide a radial-engine construction that willpermit the assembly of all pistons and of their linkagesto' a centralcluster or so-called big-end, without'and before introduction of thecrankshaft.

Other objects'and' various further features of the invention will bepointed out or will occur to those skilled in the art from a reading ofthe following specification in conjunction with the drawings includedherewith. In said drawings:

Fig. 1 is a simplified sectional view of parts of a radial engineincorporatingfeatures of the invention, the section being taken in theplane of the cylinder axes;

Fig. 2 is another view of the engine of Fig. 1, taken substantially inthe plane 22 of Fig. 1;

Fig. 3 is a view similar to Fig. 2, but with certain assembliesseparated to illustrate features of the invention;

Fig. 4 is a vertical-sectional view, in consider ably greater detail, ofparts of a radial engine illustrative'of a preferred embodiment of theinvention; and

Fig. 5 is an enlarged end view of a part of'the arrangement of Fig. 4,shown prior to its assembly with anotherpart;

Up to the present time; at least three distinct methods have beenemployed for the arrangement and assembly of the major components ofradial engines, and it is believed that a better understanding of theinvention may be had after a brief review of these three methods.

According to the first, and perhaps the oldest,

made to protrude through the respective openingsf'or the cylinders onthe outer rim of the crankcase to enable the assembly of the pistons.The removable cylinders,werethen slipped over the pistons and bolteddown upon the pads provided for their flanges on the crankcase. Inbrief, this method involved an assembly of each major unit during finalassembly;

The second method, which has been adopted by a number of prominentmanufacturers for the past several years, differed from the first mainlyin that the crankshaft was made in two pieces, while the masterconnecting .rodwas' made with a solid-ring big-end. In large enginesthis proved to be better than the first method for the reason that thesolid-ringbig-end of themaster rod provided better bearing conditions onthe whole and occupied. less space, particularly from thepoint of viewof clearance within the crankcase; To facilitate the use of thisconstruction, the main crankcase is made in two sections joinedrin theplane ofthe cylinders; with each section carrying a bearing for theassembled crankshaft. Foran accurate fitting of cylinders to thecrankcase, this-second method required fastening thetwo pieces togetherduring machining. Aside from the problems of making the crankcase in twopieces, this method, offered certain advantages as compared with thefirst general arrangementdescribed. V g

The third method forms the subject of my Patent1 ,6'70,294, issued May28, 1928. According to this third method of construction,'all connectingrods could be assembled to the crankshaft prior to incorporation in thecrankcase. The construction thus permitted a simplification of theprocess of assembling a radial engine by permitting the construction ofsub-assemblies.

Broadly speaking, the present invention contemplates furthersimplification of radial-engine assembly processes by'ca'lling for afirst sub-assembly including an open-ended crankcase with cylinders,pistons, connecting rods, and the central cluster; for asecondsub-assembly'including an end plate to fit' an end of thecrankcase and to carry a first crankcase member; and for a thirdsub-assembly including a second end plate to cover the other end of thecrankcase, and to carry bearing means for another crankshaft member!Both crankshaft members'cooperate with themselves and with the clusterto'form in effect a single crankshaft linked to'the' cluster. The threesub-assemblies maybe readily fastened to each other to complete assemblyofsubstantially the entire engine;

In the preferred specific embodiment to be described, the principalpower output from the engine is transmitted via the first crankshaftmember which includes a crankpin or offset bearing portion slidablyreceivable in the cluster. The second crankshaft member includes anoffset arm which is attached to the offset end of the first crankshaftmember after the latter has been inserted in the cluster, that is, afterthe first and second-mentioned sub-assemblies have been put together.The second crankshaft member includes a main-bearing portion which isslidably receivable in the bearing of the third sub-as sembly, so thatthe engine is substantially completely assembled When the thirdsub-assembly is fitted to the first two.

Referring to Figs. 1, 2, and 3 of the drawings, my invention is shown inapplication to a fivecylinder radial engine having five cylinders Illintegrally formed with a crankcase H. The crankcase II is preferablyannular in shape so as to provide relatively wide generally circularopenings l2 and 13 at each end. It will be understood that, if desired,the crankcase may be formed as a single annular piece without thecylinders attached, and that the cylinders may be thereafter fitted uponpads suitably machined on the annular crank-case.

The crankcase may be completed by attachment of two end-plate members Il-I5, which close off the openings I2 and [3 in the crankcase and whicheach support parts forming separate sub-assemblies.

As indicated above, my invention is characterized by essentially threesub-assemblies. The first of these, namely, that built around thecrankcase ll, preferably comprises pistons I6 within their respectivecylinders It], all pistons l6 being linked by means of suitableconnecting rods I 1 to a big-end or cluster l8. If desired, the clustermay be a solid-ring big-end integrally formed with the master connectingrod l9, or it may be pinned thereto as at alternatively, a split big-endconstruction may be employed. Also, if desired, this first or crankcaseassembly may include cylinder heads complete with valverocker arms, andother parts attached to each of the cylinders IB. These latter parts arenot shown in the drawings, but it will be clear that they may be part ofthe first sub-assembly.

A second sub-assembly is preferably built around the end plate I 4. Thissecond sub-assembly is characterized principally by a generallycentrally located bearing portion 2| providing main-bearing support fora first crankshaft member 22. The crankshaft member 22 may includeoffset bearing or crankpin means 23 for slidably fitting within thecentral bore 24 of the big-end or cluster [8; it may also be formed witha counterweighted portion 25, to permit a balancing of the fullyassembled engine. The second sub-assembly preferably is the one throughwhich principal engine output is transmitted; if adapted to thepropulsion of an aircraft, the crankshaft may be suitably coupled (bymeans not shown) to the airscrew or propeller.

A third and last sub-assembly is preferably built around the end plate[5. This third subassembly is also characterized principally by abearing portion 26 providing main-bearing support for another or secondcrankshaft member 21. The crankshaft member 27 may include an offset arm28 for cooperation with the offsetbearing portion 23 of the firstcrankshaft member 22, as well as a counterweight element 29.

The third sub-assembly preferably supports suitable power take-offmechanisms for valve-timing and for other functions. In the form shown,reduction gears 30, a valve-timing cam 3|, and cam-followers or otheractuators (not shown) may all be separately built into this thirdsubassembly.

For the arrangement described, a substantially complete radial'enginemay be form-ed by the concurrent or parallel construction of the threesub-assemblies-namely, the central or crankcase assembly, the front-endassembly, and the back-end assembly. Final assembly may be accomplishedby slidably introducing the crankpin portion 23 in the center bore 24 ofthe cluster [8 until the lip or fiange 32 of the end-plate member l4fits snugly to the crankcase and cylinder sub-assembly, as in therecessed of counterbored portion 33. When these two sub-assemblies havebeen fitted together in this manner, the crankpin portion 23 preferablyextends sufficiently for endwise engagement with the crankarm 28 of thesecond crank-shaft member 21. After inserting or otherwise associatingthe crank 28 with the crankpin 23, the third sub-assembly may be fittedto the other or back end of the crankcase sub-assembly, as by homing aflange portion 34 of the end plate I5 within a recessed or counterboredportion 35 on the crankcase ll. Suitable securing means may be providedfor positively locking the three sub-assemblies together in the mannerdescribed; in the form shown, I employ longitudinally extending boltmeans 33 pinning flange 32 into the recess 33, extending across thecrankcase through spaces between cylinders, and fastened ultimately insuitable tapped portions 31 in the flange 34 of the end-plate means l5.

Referring now to Figs. 4 and 5, I show a preferred application of theprinciples discussed general-1y above to a specific radial engine. InFig. 4 the central sub-assembly (comprising the generally annularcrankcase) cylinders, pistons, and linkages have been omitted toillustrate more clearly the arrangement of bearings and the relationshipof the crankshaft parts. The arrangement of Fig. 4 is, therefore, onlyfor the purpose of illustrating the cooperation between two of theintended three sub-assemblies. The first of these two sub-assembliesconstitutes'the front end of the finished engine and is. built around afrontend plate 38 suitably formed, as with a'circumferentially extendingflange 39, for secure and tight-fitting engagement with one side of thecentral or crankcase assembly. The front plate 38 may supportanti-friction bearing means Ail-M for free journalling of the main driveshaft 42, which is shown formed as a part of a first crankshaft member.This first crankshaft member, like the first crankshaft member of Figs.2 and 3, preferably'inclu-des a'crankpin 43 for slidable engagement withthe inner bore of the connecting-rod'cluster (not shown); The firstcrank-shaft member '42 may also include a counterweight element 44.Preferably, the structural design of the crankpin 43, and of the crankarm 45 which offsets it from the main drive shaft 42, is such as toprovide complete or substantially complete cantilevered support for the"entire thrust delivered by the assembled engine.

The, other or back-end sub-assembly is built around a back-end platemember 46, which may also include a circumferentially extending machinedportion 41 for close and tight-fitting engagement with the'crankcaseassembly. The end plate. 46.. may. include suitable.lcearingv means. 48for providing main-bearing supportfora second crankshaftmember 49... In:the form shown, this last sub-assembly. ismadeto includethe bearin48..b.ut notLthe, crankshaft member. 49, the, latter being inserted uponfinal assembly, as will later be clear. The back-end sub-assembly mayalso include suitable auxiliary shafting 50 for driving the valve-timingmechanism. In the form shown, valve timing is effected through areduction-gear train comprising a pinion i keyeqto the shaft 56, a gear52 supported on an. idler shaft 53 and meshing with the pinion St, apinion 54 driven by the idler shaft 53, and a gear 55. driven by thepinion 54; the pinionmay be formed with or locked to a. single annularcam. 56. The backend sub-assembly may also carry cam followers 5T forcooperation with the.cam'56 and suitable guide means 58.for supportingthe cam. followers 51 or other actuator means for the valve. back-endsub-assembly. is also shown to include-a number of studs 59 to receiveother auxiliary attachments for the engine, an annularly extendininlet-manifold system 66 with outlets 61 to the various cylinders, andsuitable lubricating ducts for the main-bearing surfaces.

In the final assembly of an engine according to Fig. 4, the front-endsub-assembly is preferably first fitted to the cylinder-and-crankcasesubassembly, as by introducing the crankpin 43 into the big-end cluster(not shown). ,The crankshaft member 49 is then fitted to that part ofthe crankpin which extends longitudinally beyond the back end of thecluster. In the form shown, this attachment is secured by means of atransverse pin or bolt means 62 carried by the crankshaft member 49 andfitting in a transverse groove which may be milled in the crankpin 43.

The front-end, and crankcase sub-assemblies are then ready for fittingto the third or backend sub-assembly. This fit may be accomplished byslidably introducing the main-bearing portion 63 of the crankshaftmember 49 into the inner ring of the bearing 48 and in lockingengagement with certain adapter portions of the auxiliary shaft 50.Final assembly may be completed by securing the end plates 38 and 46 tothe crankcase as by employment of longitudinally extending bolts (notshown).

In order to maintain positive drive to the auxiliary shaft 56 means maybe employed for locking shaft 50 to the crankshaft member 49. In theform shown, such connection is accomplished by providing the drive endof the shaft 56 with a projecting locating pin or stud portion 64followed by a generally cylindrical portion 65 on which a flat 66 and afiat 61 have been milled. Preferably, the flats 66 and 61 are atdifferent radial displacements from the axes of the auxiliary shaft 50.The crankshaft member 49 in turn is suitably formed with recesses andcounterbored portions to receive parts 64 and 65 of the shaft 56, and itwill be clear that the flats 66 and 61 will provide adequate locking.The fact that the flats 66 and 61 are at different displacements fromthe center of the shafts will clearly prevent any possibility of erroror ambiguity in the timed operation of the cam as a result of errors infinal assembly.

It will be appreciated that I have provided an improved structure for aradial engine, whereby simplification may be effected in thesub-assembly and in the final assembly of the principal parts.

A number of parts have been eliminated. By

The

6 fabricating the. crankcase. symmetricallyjabcut the plane. of thecylinder axes. it will be clear that machining processes may. besimplified. The arrangement is considered particularly useful from the.view point of .lowrcostmaintenance.

While. I have describedmyinvention in detail for the preferredformshown, itwill be. understood that modificationsjmay. be. madewithinthe scope of theclaimswhich follow.

I. claim:

1. Ina crankshaft, a main shaftportionfor principal power output,acrankpinportion including a cranking axis offset from the axis of saidmain shaft portion, valve-timingmeans, and a. crank portion to engagesaid crankpin portion and for driving said valve-timing means, saidcrank portion including a hub. journalled ina subassembly including saidvalve-timing means, and means within said hub and including axiallyslidable asymmetrical interlocking means for locking saidv crank portionand said valve-timing means against relative angular movement, saidinterlocking means being asymmetrically disposed about a normal section,whereby there may be a first subassembly including said valve-timingmeans and a second subassembly includingsaid crankshaft and whereby saidsubassemblies may be readily assembled to each other without thepossibility of error in the setting of said valvetiming means.

2. In a crankshaft, a power output end, a power take-off end, and anoffset crankpin portion therebetween, valve-timing cam means, said powertake-01f end and said valve-timing cam means including cooperatingaxially slidable asymmetrical interlocking means, there being suchasymmetry of said axially extending interlocking means that there may bebut one relative angular position of engagement of said power take-01fend and said valve-timing cam means, whereby said valve-timing cam meansmay be separately assembled and adjusted without the need for furtheradjustment after assembly with said crankshaft, and keying meansengaging said power take-01f end and said power-output end againstrelative angular movement about the crankpin axis, whereby said keyingmeans may positively hold alignment of the main journalled axes of saidpower-output end and of said power take-off end, and whereby the load onsaid crankpin portion may be shared by separate end bearings for saidpower-output end and for said power take-off end.

3. In an engine of the character indicated, a crankcase subassemblyincluding a crankcase open at both axial ends, a cylinder, a piston insaid cylinder, and a connecting rod connected to said piston and free insaid crankcase; a first end subassembly including a plate for one end ofsaid crankcase, and a crankshaft member journalled in said plate; and asecond end subassembly including a housin to cover the other end of saidcrankcase, a second crankshaft member, and valve-timing means connectedto said crankshaft member and self-contained within the axial limits ofsaid housing; one of said crankshaft members including a crankpin tocooperate with said connecting rod upon endwise assembly of one of saidend subassemblies with said crankcase subassembly, and the other of saidcrankshaft members including means asymmetrical about the rotary axis ofsaid crankshaft members and to be driven by said crankpin upon endwiseassembly of the other of said end subassemblies 7 with thecombinedassembly of said one end subassembly with said crankcasesubassembly.

4. In a radial engine of the character indicated, a crankcasesubassembly, and two endcover subassemblies, all said subassembliesbeing Separately assemblable and being thereafter assemblable to eachother upon end-wise sliding insertion so as to effectively close thecrankcase, a split crankshaft including two parts separately journaledin and forming part of the two of said subassemblies, said two partsincluding interengaging means asymmetrical about the rotary axis of saidcrankshaft, one 'of said end-cover subassemblies including a housing andvalve-timing means self-contained within the axial limits of saidhousing and connected to the crankshaft part in said one end-coversubassembly.

5. In a crankshaft, a main shaft portion for principal power output, acrankpin portion including a cranking axis offset from the axis of saidmain shaft portion, and a crank portion to engage said crankpin portionand including a valve-timing shaft portion and a hub, and asymmetricallocking means on said valve-timing shaft portion, said locking meansincluding two fiat surfaces parallel to the axis of said valvetimingshaft portion but at difierent radial distances therefrom, whereby uponassembly with further valve-timing means adapted to fit saidvalve-timing shaft portion there may be only one relative angularpositioning of said interlocking parts.

' GLENN D. ANGLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 284,372 Brotherhood Sept. 4, 1883692,625 Clark Feb. 4, 1902 1,256,833 Scott Feb. 19, 1918 1,447,245 GoreMar. 6, 1923 1,670,294 Angle May 22, 1928 1,921,985 Moore 1- Aug. 8,1933 2,271,011 Hubbard Jan. 27, 1942 FOREIGN PATENTS Number Country Date193,750 reat Britain Mar. 1, 1923

